Test for Trac #1814

testsuite/tests/ghc-regress/typecheck/should_fail/Tcfail186_Help.hs

+module Tcfail186_Help where
+
+type PhantomSyn a  = Int
+
+f = (\_ -> 2) :: PhantomSyn a -> Int

testsuite/tests/ghc-regress/typecheck/should_fail/all.T

@@ -172,3 +172,6 @@ test('tcfail182', normal, compile_fail, [''])
 test('tcfail183', normal, compile_fail, [''])
 test('tcfail184', normal, compile_fail, [''])
 test('tcfail185', normal, compile_fail, [''])
+test('tcfail186',
+     extra_clean(['Tcfail186_Help.hi', 'Tcfail186_Help.o']),
+     multimod_compile_fail, ['tcfail186', '-v0'])

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail186.hs

+-- Trac #1814
+
+module ShouldFail where
+
+import Tcfail186_Help
+
+foo = f "hoo"
\ No newline at end of file

testsuite/tests/ghc-regress/typecheck/should_fail/tcfail186.stderr

+
+tcfail186.hs:7:8:
+    Couldn't match expected type `PhantomSyn a'
+	   against inferred type `[Char]'
+      Expected type: PhantomSyn a
+      Inferred type: [Char]
+    In the first argument of `f', namely `"hoo"'
+    In the expression: f "hoo"